This does sound like an extremely poor experience, some flexibility and proactive service recovery would be extremely helpful. I wonder if you could ask the Inflight Service Manager to provide the regulations they quote since they should have this available to them whether in hard copy or searchable on their online systems. Not that your status should matter, but as a diamond member, I would expect them to go above and beyond to keep that member happy.

I'm taking this account on face value and am aware that there are factors that may contribute to service not occuring as it should. But if I was on this flight, this would annoy me as well.